The present invention relates in general to wireless data networking, and, more specifically, to interconnecting a wireless local area network (WLAN) to other remote local area networks.
Mobile wireless LAN devices have become popular using the IEEE 802.11 standard. WLANs provide data networking among mobile devices (e.g., laptop computers, personal digital assistants, and “smart” cellular phones) and between mobile devices and fixed devices. The range of wireless links in a WLAN, however, is typically very limited (e.g., no more than 300 meters in an IEEE 802.11b network). Thus, when a mobile user strays outside this range, their data connectivity with the WLAN is lost.
A WLAN may provide data connectivity within a business or a home office, for example, so that mobile users can access network hardware, e.g., a printer or a gateway to fixed IP networks such as the Internet. When a user moves outside the range of the WLAN, then the printer and the gateway become unavailable. It would be desirable to provide an alternative connection so that the user can restore access to the resources while out of range. It may also be desirable to share WLAN connected resources when mobile users in a group of common interest (e.g., a business or enterprise group) are spread too far apart to use an IEEE 802.11 network. In the prior art, geographically separated WLANs have been interconnected by dedicated landline links. In many potential applications, however, a fixed, landline network is impractical or too expensive.
Wireless data networking has also become available using wide area networks, such as a cellular telephone system. Cellular data modems have been integrated with cellular telephones to provide data services such as web browsing and text messaging. The general packet radio service (GPRS) standard has been defined for facilitating access to IP networks by mobile cellular devices. In the existing services, however, the mobile user is limited to using pre-configured remote applications or browsing to fixed IP resources.
In order to take advantage of developments in IP telephony, dual mode WLAN/WAN telephone devices have become available. When within range of a wireless LAN, the dual mode phone may use a WLAN interconnection to complete telephone voice calls and to conduct data sessions via an IP network. When outside the range of the WLAN, the WAN cellular transceiver is used to complete voice calls or to access data services as described above. The WLAN and WAN portions of the device separately provide point-to-point communications for the user and have not been capable of sharing resources of a WLAN.